What is the best crank ventilation method

[Steve Arndt]

http://www.youtube.com/watch?v=0xi6MilZUBA

[dscott]

Hi Steve I believe I saw your video. Is it the one where you demonstrate the vacuum by sucking colored water? How exactly would you configure the hoses? It's it safe to run just the oil filler vent straight to the exhaust check valves and run the valve cover vents to oil separator breather?

[dscott]

Oh you uploaded before I posted. Lol. Yep that video!

[Steve Arndt]

I think I used this kit. I'm not sure of the part number for the upgraded Ford check valve, going to see how long this generic one lasts.
http://www.jegs.com/i/Moroso/710/97800/ ... tId=751825


My breather plan:
CB breather tower with three stainless scrubber pads inside it. I also vent the fuel pump area to the bottom of the CB box.
Out the top of the box to a high mounted oil separator catch tank. This would be a second and final area to catch the vapors. It all would be configured to gravity train back to the case.
From the top of the upper separator is then plumbed in to the pan-e-vac.

Case sand sealed of course.

An even further improvement is to force a small amount of fresh air into the #1/2 rocker box. This creates a desirable pressure differential from the clean inlet at high pressure (relative), and out the dirty lower pressure out the exhaust evac fitting. If you have a plenum you can configure a fitting to scoop air and get the pressure difference established. More about that here:
http://www.theoldone.com/archive/pcv-breather.htm

[dscott]

Ok so I'm venting valve cover 1/2 and the oil filler to a oil separator canister which has baffles. The canister is completely sealed except for the two inlets and one outlet. I have the outlet connected with a 3/4" hose and it connects through a Napa check valve part #2-29000 to the exhaust (pan e vac). While idling I have between 2.5 and 3 inch pounds of vacuum. When rpm is raised to 3000-3500rpm I get about 4 - 4.5 inch pounds vacuum measured at the dip stick. If I rev it up high and fast it tapers to 0 or just a bit over but drops back to vacuum quickly. I want to remove the muffler next to prevent back pressure which hopefully will keep crankcase under vacuum at all times.

[Piledriver]

That'll work at no load, but under load you are going to see a lot more blowby, that is where the exhaust suction kit comes in.
It will provide vacuum that increases with load, hopefully keeping up.
If you have a turbo the suction kit goes after the ex turbine or muffler, of course.

The ~ideal setup might use some combination of manifold vacuum and exhaust vacuum, or even a vaccum pump...
On the 1.8Ts and likely other motors, VW literally uses an intentional boost leak to power a venturi vacuum generator.
(I think it primarily feeds the brake booster, but you don't have to use it that way, and it can probably (re)move some air)

[JWP]

While digging through some parts and surfing the webs, I've found a few more items I'm going to put with mine.

1. I found a compressor I bought to use with an air ride system on an old Chevy truck I had. I only ever used it for a temporary tank to test travel etc.
I hooked it up so the intake was the exhaust and exhaust was now intake. On a vacuum gauge it hits 25" hg in under a second. Next test is to put it on a larger vessel and see how long it takes to draw vacuum.

2. I found a vacuum bleed at grainger that can be used if the vacuum proves to be too much (more than 5")

3. 12v dc N/O solenoid valve.

For my purposes, I will set the pressure switch to turn on the pump and turn the valve on(closed) when at a TBD value (what ever equates to the mean vacuum for 75% throttle) to save from running the pump when just running up and down the highway. When the pump is off the separation chamber (catch tank) will vent to atmosphere, when manifold vacuum drops, the switch will close and turn on the pump, while also closing the valve resulting in vacuum on the crank case. For track days I'll install a manual override so the pump runs the entire time I'm on track which is less than 15 minutes at a time in most cases.

[Piledriver]

You are going to need to put something like a big oil filter inline on that pump to keep oil out of it, unless it is an oil based pump.
Most compact//cheap compressors are ringless with teflon-ish pistons, or graphite vane type, which destroy themselves very quickly if any oil gets in the works.

That's the main issue with the AIR pump case evac pumps (from factory with graphite vanes), the really high end $$$ built for purpose ones get UCF vanes which do tolerate oil well. The ones with G10 FG vanes REQUIRE some oil ~continuously to stay alive.
(G10 vanes work for ages in a real vacuum pump submerged in oil, but UCF (unidirectional carbon fiber) outlasts them significantly while inflicting ~zero wear to the casing, unlike dry G10, and is self lubricating, but works fine with lubricant too)

Out of the box thinking is awesome, I haven't seen my box in ages, but sometimes the little details will bite back.

I scored one of the GM electric "AIR" blowers off a mid 90s Camaro dirt cheap, and tested it for use as a vacuum pump, it actually would worked ~OK but drew 18A and had poor capacity at any significant vacuum draw.
Might make a good built-in car-vac tho.

Your vacuum accumulator/switching setup is a better plan, my vacuum accumulator doubles as a catch can and is currently about 1L. Put the vacuum break on the 3/4 rocker box, the purge sweeps the oil into the sump against windage.
(Its a cheap ricer catch can, but it has a nice sealed drain and plumbing setup)